OK so I bought a new pcm at the dealer and the speedometer is about 25 mph high. I bought a cheap laptop and I will recieve it this week. I plan on getting a cable and tunercat so that I can start tuning. How do I correct this? Also does anyone have an aldl cable that they don't need?

 

Never bought a new PCM, but shouldn't the dealer be able to load a tune for your gears?

 

25 MPG high at what true speed? The error is typically a percentage, and knowing the percentage helps figure out what the source of the error is. Could be the wrong gear ratio, wrong tire diameter, or you have an M6 program in the PCM - although that would cause indicated speed to be more than twice actual speed.

 

When I get my equipment I will have to check on that. Thanks for your replies.